Flotation process



Patented Dec. 24, 1929 UNITED STATES PATENT OFFICE.

SHERWIN P. LOWE AND HENEY T. KOENIG, OF DENVER, COLORADO, ASSIGNOBS TO B. H. CHANNING, JR., AGENT, OF SAN FRANOISCO,-CALIFORNIA FLOTATION PROCESS No Drawing.

Our invention relates to the flotation process for treating ores, and has particularly in view a means for overcoming the detrimental effect of colloidal slime in separating minerals by flotation or ofcha-nging the character of the pulp so that a more satlsfactory flotation can be accomplished. We accomplish the desired result by adding to the pulp a compound which offsets to a considerable extent the deleterious effect of the colloidal slime.

For this purpose, we have found salts of the cinchona alkaloids, which are derived from cinchona bark, to be effective. While 1 we have found cinchonine sulfate best adapted for the purpose, other salts such as hydrochloride may be used. Other alkaloids which we have tried, other than cinchonine include cinchonidine quinine and quinidine. While cinchonine is most effective, the others are of value.

The use of the added compound has the following advantages:

1. Allows a smaller amount of other flotation reagents to be used.

2. Causes the froth to form more rapidly and carry a heavier burden thus allowing a shorter time of contact in a flotation machine.

3. Gives a higher grade concentrate.

4. Gives a lower grade tailings.

An example of the use of this compound is as follows:

, A heavy sulphide ore, containing 1.8%

copper was floated, using .15 lbs. pine oil, 3

lbs. CaO, .13 lbs. xanthate, per ton of ore.

The following results were obtained Per cent copper Copper concentrates Tailings .5 The same ore was floated, using the same reagents as above, except that .007 lbs. of cinchonine sulphate per ton of ore was added before flotation. The following results were obtained:

Per cent copper Copper concentrates 11.0 Tailings .35

Application filed January 19, 1927. Serial No. 162,203.

sults were as follows:

, Per cent copper Copper concentrates 11.1 Tailings .39

The principle on which these compounds act to overcome the deleterious effect of the colloidal slime is by changing the sign of the electric charge on the colloid particles.

It is generally known, that colloids in suspension carry an electric charge, as does an ion in solution, and in this colloidal condition slimes tend to float. Salts of the cinchona alkaloids have the property of discharging this electrical charge on colloidal particles.

lVe believe ourselves to be the first to use alkaloids in a froth flotation process, the action of the alkaloids employed being to accelerate the formation of the froth; and since the use of alkaloids has been found to produce marked advantages over other agents similarly employed in overcoming the detrimental effects of colloidal slime and in accelerating the formation of the froth, it is desired to broadly claim the step of using such froth accelerating alkaloids, and it is desired to comprehend within this invention such modifications as may be necessary to adapt it to varying conditions and uses.

We claim 1. A process of concentrating ores by flotation, comprising the steps of adding a froth accelerating-alkaloid comprising cinchonine sulphate to the pulp to improve the results of the operation, and subjecting the so treated pulp to froth flotation.

2. The process of concentrating ores containing colloidal slime, comprising the steps of adding to the pulp a salt of a cinchona alkaloid which has the property of hindering flotation of the colloids, and subjecting the so treated pulp to froth flotation.

3. The process of concentrating ores containing colloidal slime comprising the steps of adding to the pulp, a salt of cinchonine Which has the property of agglomerating the colloids, and subjecting the so-trea'ted pulp to froth flotation.

4. The processof concentrating ores containing colloidal slimes which comprises adding to the ore pulp a cinchona alkaloid having the property of ag lomeratin the colloids, and subjecting the t us treate pulp to v froth flotation.

5. The rocess of concentrating ores containing co oidal slimes which comprises adding to the ore pulp a mineral acid salt of a cinchona alkaloid to accelerate the formation of froth and to agglomerate the colloids, and subjecting the thus treated pulp to froth flotation.

In testimony whereof, we afiix our'signatures.

' HENRY T. KOENIG.

SHERWIN P. 

